Voice over Internet Protocol (Voice over IP, VoIP) includes a family of methodologies, communication protocols, and transmission technologies for delivery of voice communications and multimedia sessions over IP networks, such as the Internet. The steps involved in originating a VoIP telephone call include signaling and media channel setup, digitization of the analog voice signal, encoding, packetization, and transmission as IP packets over a packet-switched network.
Call spoofing refers to the fraudulent placing of a telephone call in a manner in which the telephone infrastructure (e.g., VoIP systems) are made to believe that the call is being made by a particular party or device when in fact the call is being originated by another party. VoIP may be particularly susceptible to this type of fraud because, under VoIP, signaling and control channels may be in networks in which users have access. As a result, swatting (spoofing calls to 911 and other law enforcement services resulting in SWAT teams being deployed against unsuspecting targets) and other types of fraudulent activities are possible.
As an example of the placement of fraudulent calls, various consumer devices, such as set-top boxes (STBs), may allow users to place calls. A call request may be sent to web servers that communicate with VoIP servers, which may place the call to the requested destination and then ring the caller's designated phone or ring the caller's designated phone and immediately place a call to a destination number. In this situation, a malicious user, such as a malicious user operating through a virus or other malicious programs, may send requests to the same web server used by the consumer device (e.g., the STB) to spoof the call requests from the consumer device.